Program to Swap Alternate of an Array.

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In this article, we will write a program to swap alternate of array elements using C, C++, and Java programming languages.

The meaning of swap alternate is swapping adjacent elements of an array.

Example of swap alternate

Input:

5,6,7,8,1,4

Output:

6,5,8,7,4,1

Code in C Language

 #include<stdio.h>

 void printArray(int arr[], int n) {

    for(int i = 0; i<n; i++ ) {
        printf("%d, ",arr[i]);
    }printf("\n");

 }

 void swapAlternate(int arr[], int size) {

    for(int i = 0; i<size; i+=2 ) {
        if(i+1 < size) {
            // swap(arr[i], arr[i+1]);
            int temp = arr[i];
        arr[i] = arr[i+1];
        arr[i+1] = temp;
        }
    }

 }

 int main() {

    int even[8] = {5,2,9,4,7,6,1,0};
    int odd[5] = {11, 33, 9, 76, 43};

    swapAlternate(even, 8);
    printArray(even, 8);

    printf("\n");

    swapAlternate(odd, 5);
    printArray(odd, 5);



    return 0;
 }

Output:

2, 5, 4, 9, 6, 7, 0, 1 

33, 11, 76, 9, 43

Code in C++ Language

In this code we used swap() function.

#include<iostream>
using namespace std;

void printArray(int arr[], int n) {

    for(int i = 0; i<n; i++ ) {
        cout<< arr[i] <<" ";
    }cout<<endl;

}

void swapAlternate(int arr[], int size) {

    for(int i = 0; i<size; i+=2 ) {
        if(i+1 < size) {
            swap(arr[i], arr[i+1]);
        }
    }

}

int main() {

    int even[8] = {5,2,9,4,7,6,1,0};
    int odd[5] = {11, 33, 9, 76, 43};

    swapAlternate(even, 8);
    printArray(even, 8);

    cout << endl;

    swapAlternate(odd, 5);
    printArray(odd, 5);



    return 0;
}

Output:

2, 5, 4, 9, 6, 7, 0, 1 

33, 11, 76, 9, 43

Code in Java Language

public class Main
{
    static void swapAlternate(int[] arr, int size) {

    for(int i = 0; i<size; i+=2 ) {
        if(i+1 < size) {
            // swap(arr[i], arr[i+1]);
        int temp = arr[i];
        arr[i] = arr[i+1];
        arr[i+1] = temp;
        }
      }
    }
    
    static void printArray(int[] arr, int n) {

    for(int i = 0; i<n; i++ ) {
        System.out.print(arr[i]+" ");
     } System.out.print("\n");

    }
    
	public static void main(String[] args) {

	    int[] even = {5,2,9,4,7,6,1,0};
        int[] odd = {11, 33, 9, 76, 43};
        
		swapAlternate(even, 8);
        printArray(even, 8);
    
        System.out.print("\n");
    
        swapAlternate(odd, 5);
        printArray(odd, 5);

	}
}

Output:

2, 5, 4, 9, 6, 7, 0, 1 

33, 11, 76, 9, 43